Wide ratio transmissions with three planetary gear sets and a stationary interconnecting member

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least eight forward speed ratios and one reverse speed ratio. The transmission family members include three planetary gear sets having seven torque-transmitting mechanisms and two fixed interconnections. The powertrain includes an engine and torque converter that is continuously connected to at least one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The seven torque-transmitting mechanisms provide interconnections between various gear members, and the transmission housing, and are operated in combinations of two to establish at least eight forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingthree planetary gear sets that are controlled by seventorque-transmitting devices to provide at least eight forward speedratios and at least one reverse speed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times. The number of forward speed ratios that are availablein the transmission determines the number of times the engine torquerange is repeated. Early automatic transmissions had two speed ranges.This severely limited the overall speed range of the vehicle andtherefore required a relatively large engine that could produce a widespeed and torque range. This resulted in the engine operating at aspecific fuel consumption point during cruising, other than the mostefficient point. Therefore, manually-shifted (countershafttransmissions) were the most popular.

With the advent of three- and four-speed automatic transmissions, theautomatic shifting (planetary gear) transmission increased in popularitywith the motoring public. These transmissions improved the operatingperformance and fuel economy of the vehicle. The increased number ofspeed ratios reduces the step size between ratios and therefore improvesthe shift quality of the transmission by making the ratio interchangessubstantially imperceptible to the operator under normal vehicleacceleration.

It has been suggested that the number of forward speed ratios beincreased to six or more. Six-speed transmissions are disclosed in U.S.Pat. No. 4,070,927 issued to Polak on Jan. 31, 1978; and U.S. Pat. No.6,422,969 issued to Raghavan and Usoro on Jul. 23, 2002.

Six-speed transmissions offer several advantages over four- andfive-speed transmissions, including improved vehicle acceleration andimproved fuel economy. While many trucks employ power transmissionshaving six or more forward speed ratios, passenger cars are stillmanufactured with three- and four-speed automatic transmissions andrelatively few five or six-speed devices due to the size and complexityof these transmissions.

Seven-speed transmissions are disclosed in U.S. Pat. No. 6,623,397issued to Raghavan, Bucknor and Usoro. Eight speed transmissions aredisclosed in U.S. Pat. No. 6,425,841 issued to Haka. The Hakatransmission utilizes three planetary gear sets and six torquetransmitting devices, including two brakes and two clutches, to provideeight forward speed ratios and a reverse speed ratio. One of theplanetary gear sets is positioned and operated to establish two fixedspeed input members for the remaining two planetary gear sets. The Hakatransmission requires two double-transition shifts. Seven-, eight- andnine-speed transmissions provide further improvements in accelerationand fuel economy over six-speed transmissions. However, like thesix-speed transmissions discussed above, the development of seven-,eight- and nine-speed transmissions has been precluded because ofcomplexity, size and cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved familyof transmissions having three planetary gear sets controlled to provideat least eight forward speed ratios and at least one reverse speedratio.

In one aspect of the present invention, the family of transmissions hasthree planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, a ring gear, or aplanet carrier assembly member.

In referring to the first, second and third gear sets in thisdescription and in the claims, these sets may be counted “first” to“third” in any order in the drawings (i.e., left to right, right toleft, etc.). Additionally, the first, second or third members of eachgear set may be counted “first” to “third” in any order in the drawings(i.e., top to bottom, bottom to top, etc.) for each gear set.

In another aspect of the present invention, planet carrier assemblymembers of each of the planetary gear sets may be single pinion-carriersor double pinion-carriers.

In yet another aspect of the present invention, a first member of thefirst planetary gear set is continuously interconnected to a firstmember of the second planetary gear set and with a stationary member(transmission housing) through a first interconnecting member.

In yet another aspect of the present invention, a second member of thefirst planetary gear set is continuously interconnected to a secondmember of the second planetary gear set through a second interconnectingmember.

In yet a further aspect of the invention, each family memberincorporates an input shaft which is continuously connected with amember of the third planetary gear set and an output shaft which iscontinuously connected with another member of the third planetary gearset.

In still a further aspect of the invention, a first torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst planetary gear set with a member of the third planetary gear set.

In another aspect of the invention, a second torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thesecond planetary gear set with a member of the third planetary gear set.

In a still further aspect of the invention, a third torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with a member of the first planetary gear set.The pair of members interconnected by the third torque-transmittingmechanism are different from the pair of members interconnected by thefirst torque-transmitting mechanism.

In a still further aspect of the invention, a fourth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with a member of the second planetary gear set.The pair of members interconnected by the fourth torque-transmittingmechanism is different from the pair of members interconnected by thesecond torque-transmitting mechanism.

In a still further aspect of the invention, a fifth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with a member of the first or second planetarygear set. The pair of members interconnected by the firthtorque-transmitting mechanism is different from the pairs of membersinterconnected by the first, second, third and fourthtorque-transmitting mechanisms, respectively.

In still another aspect of the invention, a sixth torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thethird planetary gear set with another member of the first, second orthird planetary gear set. The pair of members interconnected by thesixth torque-transmitting mechanism is different from the pairs ofmembers interconnected by the first, second, third, fourth and fifthtorque-transmitting mechanisms, respectively.

In still another aspect of the invention, a seventh torque-transmittingmechanism, such as a clutch, selectively interconnects a member of thefirst or second planetary gear set with a member of the third planetarygear set. Alternatively, the seventh torque-transmitting mechanism, suchas a brake, selectively interconnects a member of the first or secondplanetary gear set with the stationary member (transmission housing).

In still another aspect of the invention, the seven torque-transmittingmechanisms are selectively engageable in combinations of two to yield atleast eight forward speed ratios and at least one reverse speed ratio.

The resulting transmission provides a significantly wider ratio spreadin comparison to transmissions with fewer speed ratios.

The above features and other features and advantages of the presentinvention are readily apparent from the following detailed descriptionof the best modes for carrying out the invention when taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1 a;

FIG. 2 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 2 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2 a;

FIG. 3 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 3 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3 a;

FIG. 4 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 4 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4 a;

FIG. 5 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 5 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5 a;

FIG. 6 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 6 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6 a;

FIG. 7 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 7 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7 a;

FIG. 8 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 8 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8 a;

FIG. 9 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 9 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9 a;

FIG. 10 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 10 a;

FIG. 11 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 11 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11 a;

FIG. 12 a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 12 b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 12 a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1 a a powertrain 10 having a conventional engine and torque converter12, a planetary transmission 14, and a conventional final drivemechanism 16.

The planetary transmission 14 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 18, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 18 includesthree planetary gear sets 20, 30 and 40.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly 26. The planet carrier assembly26 includes a plurality of pinion gears 27 rotatably mounted on acarrier member 29 and disposed in meshing relationship with both the sungear member 22 and the ring gear member 24.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear arrangement also includes seven torque-transmittingmechanisms 50, 52, 54, 56, 57, 58 and 59. The torque-transmittingmechanisms 50, 52, 54, 56 57, 58 and 59 are rotating-typetorque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the sun gear member42, and the output shaft 19 is continuously connected with the planetcarrier assembly member 46. The sun gear member 22 is continuouslyconnected with the sun gear member 32 and with the stationary member 60through the interconnecting member 70. The interconnecting member 70 maybe one component or two separate components. The ring gear member 24 iscontinuously connected with the planet carrier assembly member 36through the interconnecting member 72.

The planet carrier assembly member 36 is selectively connectable withthe planet carrier assembly member 46 through the clutch 50. The planetcarrier assembly member 36 is selectively connectable with the ring gearmember 44 through the clutch 52. The planet carrier assembly member 26is selectively connectable with the sun gear member 42 through theclutch 54. The planet carrier assembly member 26 is selectivelyconnectable with the planet carrier assembly member 46 through theclutch 56. The planet carrier assembly member 26 is selectivelyconnectable with the ring gear member 44 through the clutch 57. The ringgear member 34 is selectively connectable with the planet carrierassembly member 46 through the clutch 58. The ring gear member 34 isselectively connectable with the ring gear member 44 through the clutch59.

As shown in FIG. 1 b, and in particular the truth table disclosedtherein, the torque-transmitting mechanisms are selectively engaged incombinations of two to provide eight forward speed ratios (as well as anextra third forward speed ratio (3′)) and two reverse speed ratios.

The second reverse speed ratio (Reverse #2) is established with theengagement of the clutch 56 and the clutch 59. The clutch 56 connectsthe planet carrier assembly member 26 with the planet carrier assemblymember 46, and the clutch 59 connects the ring gear member 34 with thering gear member 44. The ring gear member 24 rotates at the same speedas the planet carrier assembly member 36. The planet carrier assemblymember 26 rotates at the same speed as the planet carrier assemblymember 46 and the output shaft 19. The sun gear member 22 and the sungear member 32 do not rotate. The speed of the planet carrier assemblymember 26 is determined from the speed of the ring gear member 24 andthe ring gear/sun gear tooth ratio of the planetary gear set 20. Thering gear member 34 rotates at the same speed as the ring gear member44. The ring gear member 34 rotates at a speed determined from the speedof the planet carrier assembly member 36 and the ring gear/sun geartooth ratio of the planetary gear set 30. The sun gear member 42 rotatesat the same speed as the input shaft 17. The speed of the planet carrierassembly member 46, and therefore the speed of the output shaft 19, isdetermined from the speed of the ring gear member 44, the speed of thesun gear member 42 and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The numerical value of the Reverse #2 speed ratiois determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30 and 40.

The first reverse speed ratio (Reverse #1) is established with theengagement of the clutch 52 and the clutch 56. The clutch 52 connectsthe planet carrier assembly member 36 with the ring gear member 44, andthe clutch 56 connects the planet carrier assembly member 26 with theplanet carrier assembly member 46. The ring gear member 22 and theplanet carrier assembly member 36 rotate at the same speed as the ringgear member 44. The planet carrier assembly member 26 and the planetcarrier assembly member 46 rotate at the same speed as the output shaft19. The sun gear member 22 and the sun gear member 32 do not rotate. Thespeed of the planet carrier assembly member 26 is determined from thespeed of the ring gear member 24 and the ring gear/sun gear tooth ratioof the planetary gear set 20. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 44, the speed of the sun gear member 42and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the Reverse #1 speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 20 and40.

The first forward speed ratio is established with the engagement of theclutch 57 and the clutch 59. The clutch 57 connects the planet carrierassembly member 26 with the ring gear member 44, and the clutch 59connects the ring gear member 34 with the ring gear member 44. The sungear member 42 rotates at the same speed as the input shaft 17. The ringgear member 44, and the planetary gear sets 20 and 30 do not rotate. Theplanet carrier assembly member 46 rotates at the same speed as theoutput shaft 19. The planet carrier assembly member 46, and thereforethe output shaft 19, rotates at a speed determined from the speed of thesun gear member 42, and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The numerical value of the first forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 40.

The second forward speed ratio is established with the engagement of theclutch 57 and the clutch 58. The clutch 57 connects the planet carrierassembly member 26 with the ring gear member 44, and the clutch 58connects the ring gear member 34 with the planet carrier assembly member46. The ring gear member 24 rotates at the same speed as the planetcarrier assembly member 36. The sun gear member 22 and the sun gearmember 32 do not rotate. The planet carrier assembly member 26 rotatesat the same speed as the ring gear member 44. The planet carrierassembly member 26 rotates at a speed determined from the speed of thering gear member 24 and the ring gear/sun gear tooth ratio of theplanetary gear set 20. The ring gear member 34 and the planet carrierassembly member 46 rotate at the same speed as the output shaft 19. Thering gear member 34 rotates at a speed determined from the speed of theplanet carrier assembly member 36 and the ring gear/sun gear tooth ratioof the planetary gear set 30. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 44, the speed of the sun gear member 42and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets20, 30 and 40.

The extra third forward speed ratio (3′) is established with theengagement of the clutch 50 and the clutch 57. The clutch 50 connectsthe planet carrier assembly member 36 with the planet carrier assemblymember 46, and the clutch 57 connects the planet carrier assembly member26 with the ring gear member 44. The ring gear member 24, the planetcarrier assembly member 36 and the planet carrier assembly member 46rotate at the same speed as the output shaft 19. The sun gear member 22and the sun gear member 32 do not rotate. The planet carrier assemblymember 26 rotates at the same speed as the ring gear member 44. Theplanet carrier assembly member 26 rotates at a speed determined from thespeed of the ring gear member 24 and the ring gear/sun gear tooth ratioof the planetary gear set 20. The sun gear member 42 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 46, andtherefore the output shaft 19, rotates a speed determined from the speedof the ring gear member 44, the speed of the sun gear member 42 and thering gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the extra third forward speed ratio (3′) isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20 and 40.

The third forward speed ratio is established with the engagement of theclutch 52 and the clutch 58. The clutch 52 connects the planet carrierassembly member 36 with the ring gear member 44, and the clutch 58connects the ring gear member 34 with the planet carrier assembly member46. The ring gear member 24 and the planet carrier assembly member 36rotate at the same speed as the ring gear member 44. The sun gear member22 and the sun gear member 32 do not rotate. The ring gear member 34 andthe planet carrier assembly member 46 rotate at the same speed as theoutput shaft 19. The ring gear member 34 rotates at a speed determinedfrom the speed of the planet carrier assembly member 36 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The sun gearmember 42 rotates at the same speed as the input shaft 17. The planetcarrier assembly member 46, and therefore the output shaft 19, rotatesat a speed determined from the speed of the ring gear member 44, thespeed of the sun gear member 42 and the ring gear/sun gear tooth ratioof the planetary gear set 40. The numerical value of the third forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 30 and 40.

The fourth forward speed ratio is established with the engagement of theclutch 50 and the clutch 52. In this configuration, the input shaft 17is directly connected with the output shaft 19. The numerical value ofthe fourth forward speed ratio is one.

The fifth forward speed ratio is established with the engagement of theclutch 52 and the clutch 54. The clutch 52 connects the planet carrierassembly member 36 with the ring gear member 44, and the clutch 54connects the planet carrier assembly member 26 with the sun gear member42. The ring gear member 24 and the planet carrier assembly member 36rotate at the same speed as the ring gear member 44. The sun gear member22 and the sun gear member 32 do not rotate. The planet carrier assemblymember 26 and the sun gear member 42 rotate at the same speed as theinput shaft 17. The planet carrier assembly member 26 rotates at a speeddetermined from the speed of the ring gear member 24 and the ringgear/sun gear tooth ratio of the planetary gear set 20. The planetcarrier assembly member 46 rotates at the same speed as the output shaft19. The planet carrier assembly member 46, and therefore the outputshaft 19, rotates at a speed determined from the speed of the ring gearmember 44, the speed of the sun gear member 42 and the ring gear/sungear tooth ratio of the planetary gear set 40. The numerical value ofthe fifth forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 20 and 40.

The sixth forward speed ratio is established with the engagement of theclutch 50 and the clutch 54. The clutch 50 connects the planet carrierassembly member 36 with the planet carrier assembly member 46, and theclutch 54 connects the planet carrier assembly member 26 with the sungear member 42. The planet carrier assembly member 26 and the sun gearmember 42 rotate as the same speed as the input shaft 17. The sun gearmember 22 and the sun gear member 32 do not rotate. The ring gear member24, the planet carrier assembly member 36 and the planet carrierassembly member 46 rotate at the same speed as the output shaft 19. Thering gear member 24, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member 26and the ring gear/sun gear tooth ratio of the planetary gear set 20. Thenumerical value of the sixth forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 20.

The seventh forward speed ratio is established with the engagement ofthe clutch 54 and the clutch 59. The clutch 54 connects the planetcarrier assembly member 26 with the sun gear member 42, and the clutch59 connects the ring gear member 34 with the ring gear member 44. Thering gear member 24 rotates at the same speed as the planet carrierassembly member 36. The sun gear member 22 and the sun gear member 32 donot rotate. The planet carrier assembly member 26 and the sun gearmember 42 rotate at the same speed as the input shaft 17. The planetcarrier assembly member 26 rotates at a speed determined from the speedof the ring gear member 24 and the ring gear/sun gear tooth ratio of theplanetary gear set 20. The ring gear member 34 rotates at the same speedas the ring gear member 44. The ring gear member 34 rotates at a speeddetermined from the speed of the planet carrier assembly member 36 andthe ring gear/sun gear tooth ratio of the planetary gear set 30. Theplanet carrier assembly member 46 rotates at the same speed as theoutput shaft 19. The planet carrier assembly member 46, and thereforethe output shaft 19, rotates at a speed determined from the speed of thering gear member 44, the speed of the sun gear member 42 and the ringgear/sun gear tooth ratio of the planetary gear set 40. The numericalvalue of the seventh forward speed ratio is determined utilizing thering gear/sun gear tooth ratios of the planetary gear sets 20, 30 and40.

The eight forward speed ratio is established with the engagement of theclutch 54 and the clutch 58. The clutch 54 connects the planet carrierassembly member 26 with the sun gear member 42, and the clutch 58connects the ring gear member 34 with the planet carrier assembly member46. The ring gear member 24 rotates at the same speed as the planetcarrier assembly member 36. The sun gear member 22 and the sun gearmember 32 do not rotate. The planet carrier assembly member 26 and thesun gear member 42 rotate at the same speed as the input shaft 17. Theplanet carrier assembly member 26 rotates at a speed determined from thespeed of the ring gear member 24 and the ring gear/sun gear tooth ratioof the planetary gear set 20. The ring gear member 34 and the planetcarrier assembly member 46 rotate at the same speed as the output shaft19. The ring gear member 34, and therefore the output shaft 19, rotatesat a speed determined from the speed of the planet carrier assemblymember 36 and the ring gear/sun gear tooth ratio of the planetary gearset 30. The numerical value of the eight forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20 and 30.

As set forth above, the engagement schedule for the torque-transmittingmechanisms is shown in the truth table of FIG. 1 b. This truth tablealso provides an example of speed ratios that are available utilizingthe ring gear/sun gear tooth ratios given by way of example in FIG. 1 b.The N_(R1)/S_(R1) value is the tooth ratio of the planetary gear set 20;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set 30;and the N_(R3)/S_(R3) value is the tooth ratio of the planetary gear set40. Also, the chart of FIG. 1 b describes the ratio steps that areattained utilizing the sample of tooth ratios given. For example, thestep ratio between the first and second forward speed ratios is 1.45,while the step ratio between the second reverse speed ratio (R2) andfirst forward ratio is −0.54. It should be noted that the single stepforward ratio interchanges are of the single transition variety.

FIG. 2 a shows a powertrain 110 having a conventional engine and torqueconverter 12, a planetary transmission 114, and a conventional finaldrive mechanism 16.

The planetary transmission 114 includes an input shaft 17 continuouslyconnected with the engine and torque converter 12, a planetary geararrangement 118, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 118 includesthree planetary gear sets 120, 130 and 140.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly 126. The planet carrierassembly 126 includes a plurality of pinion gears 127 rotatably mountedon a carrier member 129 and disposed in meshing relationship with boththe sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of pinion gears 137 rotatablymounted on a carrier member 139 and disposed in meshing relationshipwith both the sun gear member 132 and the ring gear member 134.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear arrangement 118 also includes seventorque-transmitting mechanisms 150, 152, 154, 156, 157, 158 and 159. Thetorque-transmitting mechanisms 150, 152, 154, 156, 157 and 158 arerotating-type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanism 159 is a stationary-typetorque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is continuously connected with the planet carrierassembly member 146, and the output shaft 19 is continuously connectedwith the ring gear member 144. The ring gear member 124 is continuouslyconnected with the sun gear member 132 and the stationary member 160through the interconnecting member 170. The interconnecting member 170may be one component or separate components. The planet carrier assemblymember 126 is continuously connected with the ring gear member 134through the interconnecting member 172.

The planet carrier assembly member 126 is selectively connectable withthe planet carrier assembly member 146 through the clutch 150. The ringgear member 134 is selectively connectable with the sun gear member 142through the clutch 152. The sun gear member 122 is selectivelyconnectable with the planet carrier assembly member 146 through theclutch 154. The sun gear member 122 is selectively connectable with thesun gear member 142 through the clutch 156. The planet carrier assemblymember 136 is selectively connectable with the sun gear member 142through the clutch 158. The planet carrier assembly member 126 isselectively connectable with the transmission housing 160 through thebrake 159.

The truth tables given in FIGS. 2 b, 3 b, 4 b, 5 b, 6 b, 7 b, 8 b, 9 b,10 b, 11 b and 12 b show the engagement sequences for thetorque-transmitting mechanisms to provide at least eight forward speedratios and at least one reverse ratio. As shown and described above forthe configuration in FIG. 1 a, those skilled in the art will understandfrom the respective truth tables how the speed ratios are establishedthrough the planetary gear sets identified in the written description.

As set forth above, the truth table of FIG. 2 b describes the engagementsequence of the torque-transmitting mechanisms utilized to provide areverse speed ratio and nine forward speed ratios. The truth table alsoprovides an example of the ratios that can be attained with the familymembers shown in FIG. 2 a utilizing the sample tooth ratios given inFIG. 2 b. The N_(R1)/S_(R1) value is the tooth ratio of the planetarygear set 120; the N_(R2)/S_(R2) value is the tooth ratio of theplanetary gear set 130; and the N_(R3)/S_(R3) value is the tooth ratioof the planetary gear set 140. Also shown in FIG. 2 b are the ratiosteps between single step ratios in the forward direction as well as thereverse to first ratio step. For example, the first to second step ratiois 1.91.

Turning to FIG. 3 a, a powertrain 210 includes the engine and torqueconverter 12, a planetary transmission 214, and a final drive mechanism16. The planetary transmission 214 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 218, and an output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 218 includes three planetary gear sets 220, 230 and 240.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly 226. The planet carrierassembly 226 includes a plurality of pinion gears 227 rotatably mountedon a carrier member 229 and disposed in meshing relationship with boththe sun gear member 222 and the ring gear member 224.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear arrangement 218 also includes seventorque-transmitting mechanisms 250, 252, 254, 256, 257, 258 and 259. Thetorque-transmitting mechanisms 250, 252, 254, 256, 257 and 258 arerotating type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanism 259 is stationary-typetorque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is continuously connected with the planet carrierassembly member 246, and the output shaft 19 is continuously connectedwith the ring gear member 244. The ring gear member 224 is continuouslyconnected with the sun gear member 232 and the transmission housing 260through the interconnecting member 270. The interconnecting member 270may be one component or separate components. The planet carrier assemblymember 226 is continuously connected with the ring gear member 234through the interconnecting member 272.

The planet carrier assembly member 226 is selectively connectable withthe planet carrier assembly member 246 through the clutch 250. Theplanet carrier assembly member 226 is selectively connectable with thesun gear member 242 through the clutch 252. The sun gear member 222 isselectively connectable with the planet carrier assembly member 246through the clutch 254. The sun gear member 222 is selectivelyconnectable with the sun gear member 242 through the clutch 256. The sungear member 222 is selectively connectable with the ring gear member 244through the clutch 257. The planet carrier assembly member 236 isselectively connectable with the ring gear member 244 through the clutch258. The planet carrier assembly member 236 is selectively connectablewith the transmission housing 260 through the clutch 259.

As shown in the truth table of FIG. 3 b, the torque-transmittingmechanisms are engaged in combinations of two to establish eight forwardspeed ratios (as well as an extra eighth forward speed ratio (8′)) andone reverse ratio. As previously set forth, the truth table of FIG. 3 bdescribes the combinations of engagements utilized for the eight forwardspeed ratios, the extra eighth speed ration (8′) and one reverse ratio.

The truth table also provides an example of speed ratios that areavailable with the family member described above. These examples ofspeed ratios are determined utilizing the tooth ratios given in FIG. 3b. The N_(R1)/S_(R1) value is the tooth ratio of the planetary gear set220; the N_(R2)/S_(R2) value is the tooth ratio of the planetary gearset 230; and the N_(R3)/S_(R3) value is the tooth ratio of the planetarygear set 240. Also depicted in FIG. 3 b is a chart representing theratio steps between adjacent forward speed ratios and the reverse speedratio. For example, the first to second ratio interchange has a step of2.04. It can also be readily determined from the truth table of FIG. 3 bthat all of the single step and double step forward ratio interchangesare of the single transition variety.

A powertrain 310, shown in FIG. 4 a, includes the engine and torqueconverter 12, a planetary transmission 314, and the final drivemechanism 16. The planetary transmission 314 includes an input shaft 17continuously connected with the engine and torque converter 12, aplanetary gear arrangement 318, and output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 318 includes three planetary gear sets 320, 330 and 340.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of pinion gears 327 rotatablymounted on a carrier member 329 and disposed in meshing relationshipwith both the sun gear member 322 and the ring gear member 324.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear arrangement 318 also includes seventorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359. Thetorque-transmitting mechanisms 350, 352, 354, 356, 357, 358 and 359 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 346, and the output shaft 19 is continuously connectedwith the ring gear member 344. The ring gear member 324 is continuouslyconnected with the sun gear member 332 and the stationary member 360through the interconnecting member 370. The interconnecting member 370may be one component or separate components. The planet carrier assemblymember 326 is continuously connected with the ring gear member 334through the interconnecting member 372.

The planet carrier assembly member 326 is selectively connectable withthe planet carrier assembly member 346 through the clutch 350. Theplanet carrier assembly member 326 is selectively connectable with thering gear member 344 through the clutch 352. The planet carrier assemblymember 326 is selectively connectable with the sun gear member 342through the clutch 354. The sun gear member 322 is selectivelyconnectable with the planet carrier assembly member 346 through theclutch 356. The sun gear member 322 is selectively connectable with thering gear member 344 through the clutch 357. The sun gear member 322 isselectively connectable with the sun gear member 342 through the clutch358. The planet carrier assembly member 336 is selectively connectablewith the ring gear member 344 through the clutch 359.

The truth table shown in FIG. 4 b describes the engagement combinationand the engagement sequence necessary to provide a reverse drive ratio,eight forward speed ratios (as well as an extra second forward speedratio (2′) and an extra third forward speed ratio (3′)). A sample of thenumerical values for the ratios is also provided in the truth table ofFIG. 4 b. These values are determined utilizing the ring gear/sun geartooth ratios also given in FIG. 4 b. The N_(R1)/S_(R1) value is thetooth ratio for the planetary gear set 320; the N_(R2)/S_(R2) value isthe tooth ratio for the planetary gear set 330; and the N_(R3)/S_(R3)value is the tooth ratio for the planetary gear set 340. Also given inFIG. 4 b is a chart describing the step ratios between the adjacentforward speed ratios and the reverse to first forward speed ratio. Forexample, the first to second forward speed ratio step is 1.91. It can bereadily determined from the truth table of FIG. 4 b that each of theforward single step ratio interchanges is of the single transitionvariety.

A powertrain 410, shown in FIG. 5 a, includes the engine and torqueconverter 12, a planetary transmission 414 and the final drive mechanism16. The planetary transmission 414 includes a planetary gear arrangement418, input shaft 17 and output shaft 19. The planetary gear arrangement418 includes three simple planetary gear sets 420, 430 and 440.

The planetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly 426. The planet carrierassembly 426 includes a plurality of pinion gears 427 rotatably mountedon a carrier member 429 and disposed in meshing relationship with boththe sun gear member 422 and the ring gear member 424.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the sun gear member 432 and the ring gear member 434.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear arrangement 418 also includes seventorque-transmitting mechanisms 450, 452, 454, 456, 457, 458 and 459. Thetorque-transmitting mechanisms 450, 452, 454, 456, 457, 458 and 459 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 446, and the output shaft 19 is continuously connectedwith the ring gear member 444. The sun gear member 422 is continuouslyconnected with the ring gear member 434 and the transmission housing 460through the interconnecting member 470. The interconnecting member 470may be one component or separate components. The ring gear member 424 iscontinuously connected with the planet carrier assembly member 436through the interconnecting member 472.

The planet carrier assembly member 436 is selectively connectable withthe planet carrier assembly member 446 through the clutch 450. The ringgear member 424 is selectively connectable with the sun gear member 442through the clutch 452. The planet carrier assembly member 426 isselectively connectable with the planet carrier assembly member 446through the clutch 454. The planet carrier assembly member 426 isselectively connectable with the sun gear member 442 through the clutch456. The planet carrier assembly member 426 is selectively connectablewith the ring gear member 444 through the cutch 457. The sun gear member432 is selectively connectable with the planet carrier assembly member446 through the clutch 458. The sun gear member 432 is selectivelyconnectable with the sun gear member 442 through the clutch 459.

The truth table shown in FIG. 5 b describes the engagement combinationand sequence of the torque-transmitting mechanisms 450, 452, 454, 456,457, 458 and 459 that are employed to provide two reverse drive ratiosand eight forward speed ratios (as well as an extra third forward speedratio (3′) and an extra sixth forward speed ratio (6′)).

Also given in the truth table of FIG. 5 b is a set of numerical valuesthat are attainable with the present invention utilizing the ringgear/sun gear tooth ratios shown. The N_(R1)/S_(R1) value is the toothratio of the planetary gear set 420; the N_(R2)/S_(R2) value is thetooth ratio of the planetary gear set 430; and the N_(R3)/S_(R3) valueis the tooth ratio of the planetary gear set 440. As can also bedetermined from the truth table of FIG. 5 b, all of the single stepforward interchanges are of the single transition variety.

FIG. 5 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse two ratio and first forwardratio. For example, the ratio step between the first and second forwardratios is 2.04.

A powertrain 510, shown in FIG. 6 a, includes an engine and torqueconverter 12, a planetary gear transmission 514 and the final drivemechanism 16. The planetary transmission 514 includes the input shaft17, a planetary gear arrangement 518 and the output shaft 19. Theplanetary gear arrangement 518 includes three planetary gear sets 520,530 and 540.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly 526. The planet carrierassembly 526 includes a plurality of pinion gears 527 rotatably mountedon a carrier member 529 and disposed in meshing relationship with boththe sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of pinion gears 537 rotatablymounted on a carrier member 539 and disposed in meshing relationshipwith both the sun gear member 532 and the ring gear member 534.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear arrangement 518 also includes seventorque-transmitting mechanisms 550, 552, 554, 556, 557, 558 and 559. Thetorque-transmitting mechanisms 550, 552, 554, 556, 557, 558 and 559 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 546, and the output shaft 19 is continuously connectedwith the ring gear member 544. The ring gear member 524 is continuouslyconnected with the sun gear member 532 and the transmission housing 560through the interconnecting member 570. The interconnecting member 570may be one component or separate components. The sun gear member 522 iscontinuously connected with the planet carrier assembly member 536through the interconnecting member 572.

The planet carrier assembly member 536 is selectively connectable withthe planet carrier assembly member 546 through the clutch 550. The sungear member 522 is selectively connectable with the sun gear member 542through the clutch 552. The planet carrier assembly member 526 isselectively connectable with the planet carrier assembly member 546through the clutch 554. The planet carrier assembly member 526 isselectively connectable with the sun gear member 542 through the clutch556. The planet carrier assembly member 526 is selectively connectablewith the ring gear member 544 through the clutch 557. The ring gearmember 534 is selectively connectable with the planet carrier assemblymember 546 through the clutch 558. The ring gear member 534 isselectively connectable with the sun gear member 542 through the clutch559.

The truth table shown in FIG. 6 b describes the engagement sequence andcombination of the torque-transmitting mechanisms to provide two reversespeed ratios and eight forward speed ratios (as well as an extra fourthspeed ratio (4′)). The chart of FIG. 6 b describes the ratio stepsbetween adjacent forward speed ratios and the ratio step between thesecond reverse (Reverse #2) and first forward speed ratio.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6 b. TheN_(R1)/S_(R1) wvalue is the tooth ratio of the planetary gear set 520;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set530; and the N_(R3)/S_(R3) value is the tooth ratio of the planetarygear set 540. As can also be determined from the truth table of FIG. 6b, each of the single step forward interchanges is of the singletransition variety.

A powertrain 610, shown in FIG. 7 a, has the engine and torque converter12, a planetary transmission 614 and the final drive mechanism 16. Theplanetary transmission 614 includes the input shaft 17, a planetary geararrangement 618 and the output shaft 19. The planetary gear arrangement618 includes three planetary gear sets 620, 630 and 640.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly 626. The planet carrierassembly 626 includes a plurality of pinion gears 627 rotatably mountedon a carrier member 629 and disposed in meshing relationship with boththe sun gear member 622 and the ring gear member 624.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of pinion gears 647 rotatablymounted on a carrier member 649 and disposed in meshing relationshipwith both the sun gear member 642 and the ring gear member 644.

The planetary gear arrangement 618 also includes seventorque-transmitting mechanisms 650, 652, 654, 656, 657, 658 and 659. Thetorque-transmitting mechanisms 650, 652, 654, 656, 657, 658 and 659 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 646, and the output shaft 19 is continuously connectedwith the ring gear member 644. The ring gear member 624 is continuouslyconnected with the sun gear member 632 and the transmission housing 660through the interconnecting member 670. The interconnecting member 670may be a single component or separate components. The sun gear member622 is continuously connected with the ring gear member 634 through theinterconnecting member 672.

The ring gear member 634 is selectively connectable with the planetcarrier assembly member 646 through the clutch 650. The ring gear member634 is selectively connectable with the sun gear member 642 through theclutch 652. The planet carrier assembly member 626 is selectivelyconnectable with the planet carrier assembly member 646 through theclutch 654. The planet carrier assembly member 626 is selectivelyconnectable with the sun gear member 642 through the clutch 656. Theplanet carrier assembly member 626 is selectively connectable with thering gear member 644 through the clutch 657. The planet carrier assemblymember 636 is selectively connectable with the planet carrier assemblymember 646 through the clutch 658. The ring gear member 644 isselectively connectable with the planet carrier assembly member 646through the clutch 659.

The truth table shown in FIG. 7 b describes the combination oftorque-transmitting mechanism engagements that will provide a reversedrive ratio and eight forward speed ratios, as well as the sequence ofthese engagements and interchanges.

The ratio values given are by way of example and are establishedutilizing the ring gear/sun gear tooth ratios given in FIG. 7 b. Forexample, the N_(R1)/S_(R1) value is the tooth ratio of the planetarygear set 620; the N_(R2)/S_(R2) value is the tooth ratio of theplanetary gear set 630; and the N_(R3)/S_(R3) value is the tooth ratioof the planetary gear set 640. The ratio steps between adjacent forwardratios and the third reverse to first ratio are also given in FIG. 7 b.For example, the ratio step between the first and second forward ratiois 1.50. As can also be determined from the truth table of FIG. 7 b,each of the single step forward interchanges are of the singletransition variety.

A powertrain 710, shown in FIG. 8 a, has the conventional engine andtorque converter 12, a planetary transmission 714, and the conventionalfinal drive mechanism 16. The engine and torque converter 12 aredrivingly connected with the planetary transmission 714 through theinput shaft 17. The planetary transmission 714 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 714 includes a planetary gear arrangement 718that has a first planetary gear set 720, a second planetary gear set730, and a third planetary gear set 740.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly 726. The planet carrierassembly 726 includes a plurality of pinion gears 727 rotatably mountedon a carrier member 729 and disposed in meshing relationship with thesun gear member 722. Pinion gears 728 are disposed in meshingrelationship with both the ring gear member 724 and the pinion gears727.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear arrangement 718 also includes seventorque-transmitting mechanisms 750, 752, 754, 756, 757, 758 and 759. Thetorque-transmitting mechanisms 750, 752, 754, 756, 757, 758 and 759 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 746, and the output shaft 19 is continuously connectedwith the ring gear member 744. The planet carrier assembly member 726 iscontinuously connected with the sun gear member 732 and the transmissionhousing 760 through the interconnecting member 770. The interconnectingmember 770 may be one component or separate components. The sun gearmember 722 is continuously connected with the planet carrier assemblymember 736 through the interconnecting member 772.

The planet carrier assembly member 736 is selectively connectable withthe planet carrier assembly member 746 through the clutch 750. The ringgear member 724 is selectively connectable with the planet carrierassembly member 746 through the clutch 752. The ring gear member 724 isselectively connectable with the sun gear member 742 through the clutch754. The ring gear member 724 is selectively connectable with the ringgear member 744 through the clutch 756. The ring gear member 734 isselectively connectable with the planet carrier assembly member 746through the clutch 757. The ring gear member 734 is selectivelyconnectable with the sun gear member 742 through the clutch 758. Thering gear member 744 is selectively connectable with the planet carrierassembly member 746 through the clutch 759.

The truth table of FIG. 8 b defines the torque-transmitting mechanismengagement sequence utilized for each of the eight forward speed ratiosand the reverse speed ratio. Also given in the truth table is a set ofnumerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8 b. TheN_(R1)/S_(R1) wvalue is the tooth ratio of the planetary gear set 720;the N_(R2)/S_(R2) value is the tooth ratio of the planetary gear set730; and the N_(R3)/S_(R3) value is the tooth ratio of the planetarygear set 740. As may be determined from the truth table of FIG. 8 b,each of the single step forward interchanges is of the single transitionvariety.

FIG. 8 b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.41.

A powertrain 810, shown in FIG. 9 a, has the conventional engine andtorque converter 12, a planetary transmission 814, and the final drivemechanism 16. The engine and torque converter 12 are drivingly connectedwith the planetary transmission 814 through the input shaft 17. Theplanetary transmission 814 is drivingly connected with the final drivemechanism 16 through the output shaft 19. The planetary transmission 814includes a planetary gear arrangement 818 that has a first planetarygear set 820, a second planetary gear set 830, and a third planetarygear set 840.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly 826. The planet carrierassembly 826 includes a plurality of pinion gears 827 rotatably mountedon a carrier member 829 and disposed in meshing relationship with boththe sun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of pinion gears 837 rotatablymounted on a carrier member 839 and disposed in meshing relationshipwith both the sun gear member 832 and the ring gear member 834.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847 rotatablymounted on a carrier member 849 and disposed in meshing relationshipwith both the sun gear member 842 and the ring gear member 844.

The planetary gear arrangement 818 also includes seventorque-transmitting mechanisms 850, 852, 854, 856, 857, 858 and 859. Thetorque-transmitting mechanisms 850, 852, 854, 856, 857, 858 and 859 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the planet carrierassembly member 846, and the output shaft 19 is continuously connectedwith the ring gear member 844. The ring gear member 824 is continuouslyconnected with the sun gear member 832 and the transmission housing 860through the interconnecting member 870. The interconnecting member 870may be one component or separate components. The planet carrier assemblymember 826 is continuously connected with the ring gear member 834through the interconnecting member 872.

The planet carrier assembly member 826 is selectively connectable withthe planet carrier assembly member 846 through the clutch 850. Theplanet carrier assembly member 826 is selectively connectable with thesun gear member 842 through the clutch 852. The sun gear member 822 isselectively connectable with the planet carrier assembly member 846through the clutch 854. The sun gear member 822 is selectivelyconnectable with the sun gear member 842 through the clutch 856. The sungear member 822 is selectively connectable with the ring gear member 844through the clutch 857. The planet carrier assembly member 836 isselectively connectable with the ring gear member 844 through the clutch858. The ring gear member 844 is selectively connectable with the planetcarrier assembly member 846 through the clutch 859.

The truth table shown in FIG. 9 b defines the torque-transmittingmechanism engagement sequence that provides the reverse speed ratio andeight forward speed ratios shown in the truth table and available withthe planetary gear arrangement 818. A sample of numerical values for theindividual ratios is also given in the truth table of FIG. 9 b. Thesenumerical values have been calculated using the ring gear/sun gear toothratios also given by way of example in FIG. 9 b. The N_(R1)/S_(R1) valueis the tooth ratio of the planetary gear set 820; the N_(R2)/S_(R2)value is the tooth ratio of the planetary gear set 830; and theN_(R3)/S_(R3) value is the tooth ratio of the planetary gear set 840. Itcan be readily recognized from the truth table that all of the singlestep forward interchanges are of the single transition variety. FIG. 9 balso describes the ratio steps between adjacent forward ratios andbetween the reverse and first forward ratio. For example, the ratio stepbetween the first and second forward ratios is 2.04.

The powertrain 910, shown in FIG. 10 a, includes the conventional engineand torque converter 12, a planetary transmission 914, and theconventional final drive mechanism 16. The engine and torque converter12 are drivingly connected with the planetary transmission 914 throughthe input shaft 17. The planetary transmission 914 is drivinglyconnected with the final drive mechanism 16 through the output shaft 19.The planetary transmission 914 includes a planetary gear arrangement 918that has a first planetary gear set 920, a second planetary gear set930, and a third planetary gear set 940.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly 926. The planet carrierassembly 926 includes a plurality of pinion gears 927 that are rotatablymounted on a carrier member 929 and disposed in meshing relationshipwith both the sun gear member 922 and the ring gear member 924.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937 rotatablymounted on a carrier member 939 and disposed in meshing relationshipwith both the sun gear member 932 and the ring gear member 934.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear arrangement 918 also includes seventorque-transmitting mechanisms 950, 952, 954, 956, 957, 958 and 959. Thetorque-transmitting mechanisms 950, 952, 954, 956, 957, 958 and 959 arerotating type torque-transmitting mechanisms, commonly termed clutches.

The input shaft 17 is continuously connected with the sun gear member942, and the output shaft 19 is continuously connected with the planetcarrier assembly member 946. The sun gear member 922 is continuouslyconnected with the planet carrier assembly member 936 and thetransmission housing 960 through the interconnecting member 970. Theinterconnecting member 470 may be one component or separate components.The planet carrier assembly member 926 is continuously connected withthe sun gear member 932 through the interconnecting member 972.

The planet carrier assembly member 926 is selectively connectable withthe sun gear member 942 through the clutch 950. The sun gear member 932is selectively connectable with the ring gear member 944 through theclutch 952. The ring gear member 924 is selectively connectable with thesun gear member 942 through the clutch 954. The ring gear member 924 isselectively connectable with the planet carrier assembly member 946through the clutch 956. The ring gear member 924 is selectivelyconnectable with the ring gear member 944 through the clutch 957. Thering gear member 934 is selectively connectable with the planet carrierassembly member 946 through the clutch 958. The ring gear member 934 isselectively connectable with the ring gear member 944 through the clutch959.

The truth table of FIG. 10 b describes the torque-transmitting mechanismengagement sequence utilized to provide two reverse speed ratios andeight forward speed ratios (as well as an extra first forward speedratio (1′), an extra second forward speed ratio (2′) and an extra thirdforward speed ratio (3′)). The truth table also provides a set ofexamples for the ratios for each of the reverse and forward speedratios. These numerical values have been determined utilizing the ringgear/sun gear tooth ratios given in FIG. 10 b. The N_(R1)/S_(R1) valueis the tooth ratio of the planetary gear set 920; the N_(R2)/S_(R2)value is the tooth ratio of the planetary gear set 930; and theN_(R3)/S_(R3) value is the tooth ratio of the planetary gear set 940. Ascan also be determined from the truth table of FIG. 10 b, each of thesingle step forward interchanges are of the single transition variety.

A powertrain 1010, shown in FIG. 11 a, includes the conventional engineand torque converter 12, a planetary transmission 1014, and theconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1014 through theinput shaft 17. The planetary transmission 1014 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1014 includes a planetary gear arrangement 1018that has a first planetary gear set 1020, a second planetary gear set1030, and a third planetary gear set 1040.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly 1026. The planet carrierassembly 1026 includes a plurality of pinion gears 1027 rotatablymounted on a carrier member 1029 and disposed in meshing relationshipwith both the sun gear member 1022 and the ring gear member 1024.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the sun gear member 1032 and the ring gear member1034.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with the sun gear member 1042. Pinion gears 1048 aredisposed in meshing relationship with both ring gear member 1044 and thepinion gears 1047.

The planetary gear arrangement 1018 also includes seventorque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057, 1058 and1059. The torque-transmitting mechanisms 1050, 1052, 1054, 1056, 1057and 1058 are rotating type torque-transmitting mechanisms, commonlytermed clutches. The torque-transmitting mechanism 1059 is astationary-type torque-transmitting mechanism, commonly termed a brakeor reaction clutch.

The input shaft 17 is continuously connected with the planet carrierassembly member 1046, and the output shaft 19 is continuously connectedwith the ring gear member 1044. The ring gear member 1024 iscontinuously connected with the sun gear member 1032 and transmissionhousing 1060 through the interconnecting member 1070. Theinterconnecting member 1070 may be one component or separate components.The planet carrier assembly member 1026 is continuously connected withthe ring gear member 1034 through the interconnecting member 1072.

The planet carrier assembly member 1026 is selectively connectable withthe planet carrier assembly member 1046 through the clutch 1050. Thering gear member 1034 is selectively connectable with the sun gearmember 1042 through the clutch 1052. The ring gear member 1022 isselectively connectable with the planet carrier assembly member 1046through the clutch 1054. The sun gear member 1022 is selectivelyconnectable with the sun gear member 1042 through the clutch 1056. Theplanet carrier assembly member 1036 is selectively connectable with theplanet carrier assembly member 1046 through the clutch 1057. The planetcarrier assembly member 1036 is selectively connectable with the ringgear member 1042 through the clutch 1058. The planet carrier assemblymember 1036 is selectively connectable with the transmission housing1060 through the brake 1059.

The truth table shown in FIG. 11 b describes the engagement combinationsand the engagement sequence necessary to provide a reverse drive ratioand nine forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 11 b. These valuesare determined utilizing the ring gear/sun gear tooth ratios also givenin FIG. 11 b. The N_(R1)/S_(R1) value is the tooth ratio for theplanetary gear set 1020; the N_(R2)/S_(R2) value is the tooth ratio forthe planetary gear set 1030; and the N_(R3)/S_(R3) value is the toothratio for the planetary gear set 1040. Also given in FIG. 11 b is achart describing the step ratios between the adjacent forward speedratios and the reverse to first forward speed ratio.

A powertrain 1110 shown in FIG. 12 a includes the conventional engineand torque converter 12, a planetary transmission 1114, and aconventional final drive mechanism 16. The engine and torque converterare drivingly connected with the planetary transmission 1114 through theinput shaft 17. The planetary transmission 1114 is drivingly connectedwith the final drive mechanism 16 through the output shaft 19. Theplanetary transmission 1114 includes a planetary gear arrangement 1118that has a first planetary gear set 1120, second planetary gear set1130, and a third planetary gear set 1140.

The planetary gear set 1120 includes a sun gear member 1122, a ring gearmember 1124 and a planet carrier assembly member 1126. The planetcarrier assembly member 1126 includes a plurality of pinion gears 1127rotatably mounted on the carrier member 1129 and disposed in meshingrelationship with both the sun gear member 1122 and the ring gear member1124.

The planetary gear set 1130 includes a sun gear member 1132, a ring gearmember 1134 and a planet carrier assembly member 1136. The planetcarrier assembly member 1136 includes a plurality of pinion gears 1137rotatably mounted on the carrier member 1139 and disposed in meshingrelationship with the sun gear member 1132. Pinion gears 1138 aredisposed in meshing relationship with both the ring gear member 1134 andthe pinion gears 1137.

The planetary gear set 1140 includes a sun gear member 1142, a ring gearmember 1144, and a planet carrier assembly member 1146. The planetcarrier assembly member 1146 includes a plurality of pinion gears 1147rotatably mounted on the carrier member 1149 and disposed in meshingrelationship with both the sun gear member 1142 and the ring gear member1144.

The planetary gear arrangement 1118 also includes seven torquetransmitting mechanisms 1150, 1152, 1154, 1156, 1157, 1158 and 1159. Thetorque-transmitting mechanisms 1150, 1152, 1154, 1156, 1157 and 1158 arerotating type torque-transmitting mechanisms, commonly termed clutches.The torque-transmitting mechanism 1159 is a stationary typetorque-transmitting mechanism, commonly termed a brake or reactionclutch.

The input shaft 17 is continuously connected with the planet carrierassembly member 1146, and the output shaft 19 is continuously connectedwith the ring gear member 1144. The ring gear member 1124 iscontinuously connected with the sun gear member 1132 and thetransmission housing 1160 through the interconnecting member 1170. Theinterconnecting member 1170 may be one component or separate components.The planet carrier assembly member 1126 is continuously connected withthe planet carrier assembly member 1136 through the interconnectingmember 1172.

The planet carrier assembly member 1126 is selectively connectable withthe planet carrier assembly member 1146 through the clutch 1150. Theplanet carrier assembly member 1126 is selectively connectable with thesun gear member 1142 through the clutch 1152. The sun gear member 1122is selectively connectable with the planet carrier assembly member 1146through the clutch 1154. The sun gear member 1122 is selectivelyconnectable with the sun gear member 1142 through the clutch 1156. Thesun gear member 1122 is selectively connectable with the ring gearmember 1144 through the clutch 1157. The ring gear member 1134 isselectively connectable with the ring gear member 1144 through theclutch 1158. The planet carrier assembly member 1126 is selectivelyconnectable with the transmission housing 1160 through the brake 1159.

The truth table shown in FIG. 12 b describes the engagement combinationsin the engagement sequence necessary to provide a reverse drive ratioand eight forward speed ratios (as well as an extra eight forward speedratio (8′)). A sample of the numerical values for the ratios is alsoprovided in the truth table of FIG. 12 b. These values are determinedutilizing the ring gear/sun gear tooth ratios also given in FIG. 12 b.The N_(R1)/S_(R1) value is the tooth ratio for the planetary gear set1120; the N_(R2)/S_(R2) value is the tooth ratio for the planetary gearset 1130; and the N_(R3)/S_(R3) value is the tooth ratio for theplanetary gear set 1140. As can be determined from FIG. 12 b, each ofthe single step and double step interchanges is of the single transitionvariety. Also given in FIG. 12 b is a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second and third planetary gear sets having first, secondand third members; said input shaft being continuously interconnectedwith a member of said third planetary gear set, and said output shaftbeing continuously interconnected with another member of said thirdplanetary gear set; a first interconnecting member continuouslyinterconnecting said first member of said first planetary gear set withsaid first member of said second planetary gear set and with astationary member; a second interconnecting member continuouslyinterconnecting said second member of said first planetary gear set withsaid second member of said second planetary gear set; a firsttorque-transmitting mechanism selectively interconnecting a member ofsaid first planetary gear set with a member of the third planetary gearset; a second torque-transmitting mechanism selectively interconnectinga member of said second planetary gear set with a member of said thirdplanetary gear set; a third torque-transmitting mechanism selectivelyinterconnecting a member of said third planetary gear set with a memberof said first planetary gear set, the pair of members interconnected bysaid third torque-transmitting mechanism being different from the pairof members interconnected by said first torque-transmitting mechanism; afourth torque-transmitting mechanism selectively interconnecting amember of said third planetary gear set with a member of said secondplanetary gear set, the pair of members interconnected by said fourthtorque-transmitting mechanism being different from the pair of membersinterconnected by said second torque-transmitting mechanism; a fifthtorque-transmitting mechanism selectively interconnecting a member ofsaid third planetary gear set with a member of said first or secondplanetary gear set, the pair of members interconnected by said fifthtorque-transmitting mechanism being different from said pairs of membersinterconnected by said fist, second, third and fourthtorque-transmitting mechanisms, respectively; a sixthtorque-transmitting mechanism selectively interconnecting a member ofsaid third planetary gear set with another member of said first, secondor third planetary gear set, the pair of members interconnected by saidsixth torque-transmitting mechanism being different from said pairs ofmembers interconnected by said first, second, third, fourth and fifthtorque-transmitting mechanisms, respectively; and a seventhtorque-transmitting mechanism selectively interconnecting a member ofsaid first or second planetary gear set with a member of said thirdplanetary gear set, or with said stationary member; saidtorque-transmitting mechanisms being engaged in combinations of two toestablish at least eight forward speed ratios and at least one reversespeed ratio between said input shaft and said output shaft.
 2. Thetransmission defined in claim 1, wherein said first, second, third,four, fifth and sixth torque-transmitting mechanism comprise clutches,and said seventh torque-transmitting mechanism comprises a brake.
 3. Thetransmission defined in claim 1, wherein said first, second, third,fourth, fifth, sixth and seventh torque-transmitting mechanisms compriseclutches.
 4. The transmission defined in claim 1, wherein planet carrierassembly members of each of said planetary gear sets are single-pinioncarriers.
 5. The transmission defined in claim 1, wherein at least oneplanet carrier assembly member of said planetary gear sets is adouble-pinion carrier.
 6. A multi-speed transmission comprising: aninput shaft; an output shaft; a planetary gear arrangement having first,second and third planetary gear sets, each planetary gear set havingfirst, second and third members; said input shaft being continuouslyinterconnected with a member of said third planetary gear set, saidoutput shaft being continuously interconnected with another member ofsaid third planetary gear set; a first interconnecting membercontinuously interconnecting said first member of said first planetarygear set with said first member of said second planetary gear set andwith a stationary member; a second interconnecting member continuouslyinterconnecting said second member of said first planetary gear set withsaid second member of said second planetary gear set; and seventorque-transmitting mechanisms for selectively interconnecting saidmembers of said planetary gear sets with a stationary member or withother members of said planetary gear sets, said seventorque-transmitting mechanisms being engaged in combinations of two toestablish at least eight forward speed ratios and at least one reversespeed ratio between said input shaft and said output shaft.
 7. Thetransmission defined in claim 6, wherein a first of said seventorque-transmitting mechanism is operable for selectivelyinterconnecting a member of said first planetary gear set with a memberof said third planetary gear set.
 8. The transmission defined in claim6, wherein a second of said seven torque-transmitting mechanism isoperable for selectively interconnecting a member of said secondplanetary gear set with a member of said third planetary gear set. 9.The transmission defined in claim 6, wherein a third of said seventorque-transmitting mechanisms is selectively operable forinterconnecting a member of said third planetary gear set with a memberof said first planetary gear set, the pair of members interconnected bysaid third torque-transmitting mechanism being different from a pair ofmembers interconnected by a first of said seven torque-transmittingmechanisms.
 10. The transmission defined in claim 6, wherein a fourth ofsaid seven torque-transmitting mechanism is selectively operable forinterconnecting a member of said third planetary gear set with a memberof said second planetary gear set, the pair of members interconnected bysaid fourth torque-transmitting mechanism being different from a pair ofmembers interconnected by a second of said seven torque-transmittingmechanisms.
 11. The transmission defined in claim 6, wherein a fifth ofsaid seven torque-transmitting mechanisms is selectively operable forinterconnecting a member of said third planetary gear set with a memberof said first or second planetary gear set, the pair of membersinterconnected by said fifth torque-transmitting mechanism beingdifferent from pairs of members interconnected by a first, second, thirdand fourth of said seven torque-transmitting mechanisms, respectively.12. The transmission defined in claim 6, wherein a sixth of said seventorque transmitting mechanisms selectively interconnects a member ofsaid third planetary gear set with another member of said first, secondor third planetary gear set, the pair of members interconnected by saidsixth torque-transmitting mechanism being different from pairs ofmembers interconnected by a first, second, third, fourth and fifth ofsaid seven torque-transmitting mechanisms, respectively.
 13. Thetransmission defined in claim 6, wherein a seventh of said seventorque-transmitting mechanisms selectively interconnects a member ofsaid first or second planetary gear set with a member of said thirdplanetary gear set, or with said stationary member.
 14. The transmissiondefined in claim 6, wherein planet carrier assembly members of each ofsaid planetary gear sets are single-pinion carriers.
 15. Thetransmission defined in claim 6, wherein at least one planet carrierassembly member of said planetary gear sets is a double-pinion carrier.